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Question #45755
The Question
The maintenance of the medullary interstitial osmotic gradient and its utilization are critical for urine concentration. Which of the following statements is INCORRECT regarding these physiological and ecological dynamics?
Options
- A.
The thick ascending limb of the Loop of Henle acts as a metabolic sink, utilizing ATP to actively transport NaCl into the medullary interstitium.
- B.
Similar to how an inverted biomass pyramid relies on the high turnover rate of phytoplankton, the counter-current multiplier relies on continuous active transport to maintain the standing medullary gradient.
- C.
In Diabetes Insipidus, the systemic failure to concentrate urine occurs because the deficiency of ADH causes the collapse of the hyperosmolar medullary interstitial gradient.
- D.
Small amounts of urea enter the thin ascending limb of Henle's loop and are later transported back to the medullary interstitium by the collecting duct.
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Correct Answer
Step-by-Step Solution
Explanation
How the Examiner Thinks
Comparative_Analysis
Sharpen your ability to evaluate multiple scenarios and distinguish between competing potential answers.
Concepts Behind This Question
Diuretic Dynamics|Inverted Biomass Pyramids|Nutrient Immobility
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Distinguishing between the 'generation/maintenance' of the osmotic gradient (Loop of Henle/Vasa Recta) and the 'utilization' of the gradient (ADH acting on the Collecting Duct).
Common Misconception: Students frequently assume that an inability to concentrate urine (as seen in Diabetes Insipidus) implies the underlying medullary gradient itself has been destroyed, conflating the 'retention mechanism' (ADH/Aquaporins) with the 'gradient generator' (Counter-current multiplier).
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Excretory Products and Their Elimination - Class 11 |
| Concept | Diuretic Dynamics |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |